Hughes, Paul L.
Littlefield, Adams, 1956
Buku Teks
Weber, Eugen
Boston: D.C.Heath and Company, (1959).
Buku Teks
Burckhardt, Jacob
Harper Torchbooks, 1968
Buku Teks
Hale, John R.
Time-Life International, 1969
Buku Teks
edited with an introd. by Edward H. Weatherly
Dell Publishing, 1962
Buku Teks